Century/Closed Figure/Closure
CENTURY A period of one hundred years.
CLOSED FIGURE A geometric figure that entirely encloses part of the plane.
CLOSURE A property of a set of numbers such that the operation with two or more numbers of that set results in a number of the set. Example: In addition and multiplication with counting numbers, the results is a counting numbers. 2 + 4 = 6; 2 x 4 = 8
Thus, the counting numbers are closed under these two operations.
In subtraction, if 4 is subtracted from 2, the result (-2) is not a counting number. Also in dividing a 2 by 4, the results (1/2) is not a counting number. Thus, the counting numbers are not closed with respect to subtraction and division.